Laws of Motion

Newton's laws can be found in most of the sports and other activities that children participate in. Some examples:

- You have to pedal a bicycle hard and fast to get going because of inertia. You have to brake hard and can't stop instantly due to momentum.(First Law of Motion)

- Getting a ball to go where you want it to go is a matter of applying the correct force in the correct direction. (Second Law of Motion)

- Things that happen when you are skating (roller or ice) and pushing or pulling each other (as in hockey) are governed by action-reaction. (Third Law of Motion)

There are lots of other applications of Newton's Laws of Motion to such activities. Just think about all of the motion involved and the forces needed to produce the motion and you will see them.

You could ask your students to give you a sport or activity and something that happens in that sport or activity and you could analyze it and tell them the forces and motion involved and how the Laws of Motion apply.

Newton's First Law:

Part 1 (Inertia): An object at rest will remain at rest unless acted upon by an unbalanced force.

In volleyball: The ball will not go anywhere until someone serves it.

Part 2: (momentum): An object in motion will remain in motion in a straight line at a constant speed unless acted upon by an unbalanced force.

In volleyball: Once served the ball will travel in an arc due to earth's gravity but will go in one direction only unless someone hits it to change its direction or speed. Then it will continue in the new direction and speed until someone else hits it.

Newton's Second Law:

Force equals mass times acceleration: f = m X a

In volleyball: The harder you hit the ball the faster it will go it whatever direction you hit it. Also, the ball won’t go over the net unless you hit it hard enough. Also, if you hit the ball too hard it will go out of bounds. Also, a lighter ball will go farther and faster than a heavier ball.

Newton's Third Law:

For every action there is an equal and opposite reaction.

In volleyball: The ball hits your hand just as hard as you hit the ball. To avoid injuring your fingers, hold your hand in the proper position. Also, to make the ball go where you want it to go your must hit it in the proper spot with the proper force.

I do something that really grabs them. I have a silky piece of material large enough to cover a small table or student desk and hang down a bit all around. I set the table with clean dishes I get at yard sales or the dump. Without saying a word, I walk up to the table and gather the cloth in my hands. At this point, they are staring at me in disbelief, and then, "Voila!" I pull the table cloth out from under the dishes without rattling a single one. Is it magic? No, it's science. I then ask them what they observed and teach them about force and motion. "An object at rest will remain at rest unless acted on by an outside force."

Since my table covering has no hem, and there is little friction because of the type of material, there is no force to move the dishes. I make sure to explain that they are not to use the good china at home and that these dishes are dump dishes, and then proceed to have students take a risk until everyone has been successful. You can hear the dishes shattering all over the school! We do a lot of observation and sharing of what we see leads to success, and eventually, everyone accomplishes the task. It's great fun, educational, and a confidence builder!

We had fun using a slanted board covered with different material (a towel, sandpaper, slick mirror, etc) the children race little hot wheels cars; some are heavier than others. Also slide down erasers, coins, washers to show drag. Prop a piece of plywood with several books. Since I was lucky enough to have the services of two aides, we set up stations so groups of four could do each activity as they moved around the room.

Glue a metal washer in the center of a piece of computer paper prior to the day of the activity. Have one paper per group; I normally have students work in pairs.

Students place a marble on the washer. If the paper is pulled toward you, quickly and straight out, the marble will remain in place.

I just finished teaching a unit about Newton's Laws of Motion. To introduce the third law, I hung two styrofoam balls from the ceiling at the same height. I then blew on one of the balls, so that it would hit the other one. We did this a few times, discussing why the second ball moved. (They all wanted to swing the balls.) We talked about air being the force, and what would happen if we changed the speed of the air.

I then asked them what would happen if I blew in between the balls (they predicted that each ball would move away from the air flow). I then demonstrated that when you blow in between the balls, they will move close to eachother instead of away. This brought on the discussion of other forces, such as air pressure and gravity. (The balls moved together because when I blew the air in between them, the moving air created a low pressure area. The high pressure area all around the ball, caused air to rush in to the low pressure area, taking the balls with it.) My kids really got a kick out of that.

We also took two marbles and tried to roll them into each other. You can see how the direction changes if you dip the marbles in paint first.

To introduce the idea of objects moving by a push or a pull (force), I gave each pair of students a small empty container (saved those small play dough containers or empty film containers). They were given the instruction to see how many different ways they could make their object move. Each partner took turns testing their idea and the other recorded their idea on a 3x5 card. After 5 minutes, we had time to go around the room and have the groups demonstrate one of their ideas. They actually were able to show 12-13 different ways. This led into a discussion on gravity and motion. Some discovered they could move their object with a magnet if they added a metal object inside the container. Anyway, it was a great segway.

I love Newton's third law. It is so much fun to prove.

Have your students make balloon rockets. Simply a balloon that is taped to a straw. Thread a piece of string through the straw and have them let go of the balloon. Action.. air being released from the balloon.. reaction.. it's movement. This is exactly how a rocket is shot into space.

This is my 1st year teaching 6th grade science and here are a couple ethings I did for the 3 laws of motion:

1. Have them make collage posters with magazine pics of examples of the laws, (make captions to explain them)

2. Today we did a balloon race lab. With fishing line as the track and balloons taped to straws. A great example of Newton's 3rd Law.

Friction: toy car moving across or rolling down surfaces with different textures

Centrifugal Force: bucket of water you swing around over your head

Roller Coaster Physics:
materials needed: foam chutes, marbles, masking tape
Students in small groups connect foam tubes that have been cut in half to become roller coasters for their marble. They experiment with different tests and modifications (spirals, loop-the-loops, etc.)to move the marble from the beginning of their roller coaster to the end.

You can discuss stored and potential energy here; friction--how the marble moves a little slower, perhaps, over the masking taped areas vs. the smooth foam; kinetic energy--once the marble is in motion; Newton's Laws of Physics (Inertia--object at rest stays at rest and an object in motion stays in motion unless acted upon by a force; F=ma--relating this to speed and size/weight of marble; For every action there is an equal and opposite reaction--students can predict in a demo where they think a marble will end up when the demo roller coaster has several hills of different heights.)

Drag:
Use tissues to demo what will hit the ground faster: two tissues both as is; one tissue as is, the other balled.

I use the digital camera to take pictures of the class playing and doing things that exhibit forces in motion.

Hula hoop and jumping rope centrifical forces

gravitational forces cars rolling down a ramp

throwing different kinds of balls

doing some of their science experiments on force and motion, etc.

Newton's Laws of Motion can be taught with rocketry. You can do anything from balloon rockets to Estes chemical rockets depending on time and budget. NASA's website is a huge resource for educational materials in all branches of science. Just one of their publications is one on Rockets. It is in pdf format on line or you can get it through the mail from any NASA installation. I have enjoyed the alkaselzer rockets and the 2-liter soda bottle rockets.